In a full-automatic biochemical analyzer, a reaction cuvette is rinsed by using detergent with certain concentration. However, such detergent is generally kept in a concentrated state when it is being transported and stored. Therefore, in order to obtain the detergent with appropriate concentration, the full-automatic biochemical analyzer also provides a function to automatically dilute the concentrated detergent before it is used to rinse the reaction cuvette. In this way, biohazards caused by manual operations may be avoided.
The dilution of detergent refers to uniformly mix the concentrated detergent with deionized water in a certain volume ratio. Conventional diluting methods include on-site dilution and liquid-storage dilution. In on-site dilution, the detergent is not diluted until the reaction cuvette is going to be rinsed. In this case, all the diluted detergent produced in a dilution process would be used up one time during the subsequent rinsing process of the reaction cuvette. In contrast, during the liquid-storage dilution, a certain amount of detergent is diluted and stored in advance, and then the diluted detergent would be used at any time thereafter for rinsing the reaction cuvettes.
Compared with the liquid-storage dilution, the drawbacks of the on-site dilution lie in that the biochemical analyzer operates too frequently, and in that the dilution ratio is difficult to be guaranteed since the amount of diluted liquid for each dilution process is very small and thereby the flow rate is difficult to control. However, the liquid-storage dilution can accurately control the flow-rate and decrease the frequency of biochemical analyzer's operation. Therefore, the liquid-storage dilution is widely applied.
In conventional liquid-storage dilution, it is typically by means of dosing pumps, injectors, high-pressure gas or gravities of their own, to drive the deionized water and the concentrated detergent into a liquid-storage container. But, the dosing pumps and injectors are costly, while driving with gravities of their own is not reliable and difficult to quantify. For this reason, the liquid-storage dilution driven by high-pressure gas is becoming popular.
According to the conventional method for liquid-storage dilution with use of high-pressure gas, the liquid-storage container is required to be kept in a low pressure (e.g., environmental pressure) during a dilution process, so that deionized water and concentrated detergent can be driven into a liquid-storage container by high-pressure gas. Then, during a rinsing process, the liquid-storage container is required to be kept in a high pressure, since the diluted detergent within the liquid-storage container should be driven into a reaction cuvette, which is kept in a low pressure. In order to avoid interference between the diluting and rinsing processes, the two processes are carried out separately, i.e., within two separate containers and having two separate sets of apparatus for control. This results in high cost and high complexity of a system for both diluting and rinsing.
Furthermore, according to the conventional method for liquid-storage dilution as above, the diluting process is not triggered until diluted detergent within the liquid-storage container is used up. Only when it is used up, a predetermined amount of deionized water and concentrated detergent are driven into the liquid-storage container. As a result, the diluting process would not be triggered if the diluted detergent within the liquid-storage container is consumed partly. Further, even if a diluting process is triggered, the dilution ratio cannot be guaranteed due to inability to determine the amount of deionized water and concentrated detergent that need to be driven into.
Therefore, there is a need for an apparatus and method for auto-diluting and rinsing, which can reduce costs and trigger the diluting process at any moment while keeping the dilution ratio.